The present invention relates to molds and methods for making molds.
Numerous products are manufactured by molding. For relatively large products, such as certain components of recreational vehicles, a mold is typically made by creating a pattern and pulling the mold from the pattern.
It is known to produce patterns by assembling an assortment of wood, foam and metal scraps corresponding to the general shape of the part to be produced. Once this base has been formed, it is covered with an epoxy material and cut, sanded or otherwise shaped to form the pattern, The pattern is then smoothed. and ready for use. To form the mold, the pattern is covered with, a thermosetting plastic material that is allowed to harden. The mold is then pulled from the pattern and is ready for use.
There are several problems with this known method of making a pattern and a mold. First, the process is time consuming. Second, the final appearance of the part cannot be determined until the pattern is almost complete. Additionally, if at this late stage any changes are desired, they may be difficult and time consuming to make, involving cutting away entire portions of the pattern and rebuilding them from scratch.
A method of making a mold according to the present invention includes the steps of determining the contours of the part to be produced from the mold, forming a plurality of pattern stations each having a surface conforming at least in part to a contour of the part at a given location, placing the pattern stations in spaced apart relationship, filling the spaces between the pattern stations, vacuum forming a plastic material to a portion of the pattern and applying a mold making material. The stations may be angled relative to one another and may intersect. The stations may be made from wood, foam or other material. A release agent may be applied to the vacuum formed plastic material. Also, a gelcoat material may be applied and sanded. The gelcoat material may be waxed. One or more female pattern stations may be cut and positioned over the pattern stations to check for proper alignment. A metal sheet may be attached to the pattern stations prior to filling the spaces between the pattern stations.
According to another embodiment of the present invention, a method of making a mold includes the steps of determining the contours of the part to be produced from the mold, forming a plurality of pattern stations each having a surface conforming at least in part to a contour of the part at a given location, joining the pattern stations together such that their surfaces form substantially the complete contour of the part and covering a portion of the pattern with a plastic material. The pattern stations may be releasibly joined together such that one or more pattern stations may be removed and substituted with one or more different pattern stations. Plastic material may be vacuum formed to the pattern stations. A release agent, gelcoat material and mold making material may also be applied in alternative embodiments.
In another embodiment of the present invention, a method of making a mold includes the steps of determining the contours of the part to be produced from the mold, forming a cavity corresponding to the contours of the part to be produced from the mold, vacuum forming a plastic material in the cavity and applying a mold making material. The cavity may be formed by cutting the contours of the object at various locations in sheets of material and joining the sheets together. A release agent and/or gelcoat material may be applied.
Other aspects and novel features of the present invention will now be apparent to those skilled in the art from consideration of the detailed description of the preferred embodiments and accompanying drawings.